Electric switch



ELECTRIC SWITCH Filed July 3. 1936 2 Sheets-Sheet l Fly] BY ATTORNEYS March 8, 1938. H. NABAKowsK 2,110,233 l ELECTRI C SWITCH Filed July 3, 1955 2 Sheets-Sheet 2 A Tron/v5 YJ Patented Mar. 8, 1938 PATENT :OFFICE ELECTRIC SWITCH Hermann Nabakowski, Berlin, Germany Application .myv 8, 193e, serial N'o. 88,847

Germany July 4,4 1935 5 Claims. l (Cl. 200-167) This invention relates to tumbler switches for electric circuits and provides for a switch of the kind which indicates its aixed location by means of a glowing lamp, especially an incandescent lamp, fitted in the lamp-holder and which glows when the switch is switched off.

'Ihe arrangement of lamps in switches and particularly that of glow lamps, has already been suggested. In the case of rotary switches, for example, a lamp has been successfully xed in the middle of the switch-handlewith the lamp adapted to shinel through the transparent handle. Other adaptations have likewise been proposed i and a number of persons have succeeded in manufacturing various kinds of such switches in the customary dimensions of the ordinary electric switch, with reference both to switches for application tothe surface of a wall and for those to be hidden within or by a wall. 4

With referenceto tumbler switches, however, no o ne has yet succeeded in solving the problem of incorporating a glow lamp, insofar as this inventor knows, asin the usual restricted sizes of these particular switches there is very little space for a lamp in addition to the operating parts of the switch and no satisfactory accommodation for such parts beside the lamp.

The present invention successfully eliminates all the prevailing diiiiculties and provides a practical tumbler switch With lamp embodiment. This is achieved by fastening the lamp to the switch-base, which is preferably made of pressboard, by means of a tubular sleeve-bushing forming at its upper end a bearing for a forked conductor, connecting the junction-contacts with one another or cutting them, as may be required, connecting the said conductor with a similar forked switch handle by an arrangement of spring, and mounting the switch handle to pivot upon an axis positioned parallel to the pivotal axis of the conductor formed as a swing hoop or yoke, and to rest on the base itself. l

The invention is illustrated by the attached drawings, in which:

Fig.`1 represents a vertical section through th switch on the plane in which the axis of rotation of the handle and also of the moving contact lies;

Fig. 2 is an alternate section of the a angle to Fig. 1;

Fig. 3 is a top view of the lower partof the switch without the bridge-contact-piece and handle; and

Fig. 4 is a top view of the switch-cap. In the illustrative construction, the lamp I, in-

switch on dicating the location of the switch and comprising a so-called dwarf-glowlamp, is xed into the switch-base 5, preferably made of pressboard, by means of a shell-like socket member or sleevebushing 2 made of insulating material and internally threaded to receive the lamp screwed thereinto. This socket or bushingZ is formed in this instance with two opposite laterally disposed wing-lugs or joining-pieces 3, at its lower end, which are turned in behind or under shoulders (see Fig. 2),*'provided in said base 5, like a bayonet-joint as indicated in dotted lines in Fig. 3. In this position said lugs or joining-pieces bear or rest against an arresting-surface 6 which may advantageously comprise a part of the base, and so hold the bushing iirmly in place. The bushing having been inserted in this manner can then be permanently connected with the base 5 as for instance by casting.

At its upper end the aforenamed bushing 2 is formed with two upwardly extending arched portions oppositely disposed at 90 degrees to the lower end jointing lugs. 'I'he peaks of these arched portions are reinforced by lateral enlargements 8 outward, and said enlargements constituting two ear-like projections are arcuated or indented upwardly to form downwardly directed cavities. Into these cavities is inserted with correspondingly rounded-off extremities 9 the opposite arms of a U-shaped or hoop-like swing contact-piece I0, II, a side view of which is presented in Fig. 2. Opposite the extremities 9, the

arms of said hoop-like contact I0, I I are provided with bent 'flaps I2 cooperating with connectingspringsattached to the switch lever and thus effecting the corresponding connections. The upper end of each of said aps I2 is shaped into an effective hook I3 with which is engaged the suspending end of a helical spring I4 at opposite sides of the socket or bushing member 2.

v`The movable contact piece I0, II is given a swing movement to opposite positions by a forkshaped swing lever or handle I5, to which the upper ends of the aforenamed springs I4 are xed atvII. The two arms I'I of this fork lever are vtension by the springs I4. 'I'his forked lever I5 is thus adapted to swing upon an axis within the base parallel to the pivotal or swing axis of the conductor contact I0, II Itis preferable to provide for said lever axis substantially removed from and below said contact axis, and it is so shown lower in or closer to the bottom of the switch base than said other axis, so as to secure the best result.` From the foregoing description and drawings it will be seen that a dead-centre snap-swing" action is provided by this construction, eifectuated by the springs I4 connected between the switch lever and the contact membe whereby said member II), II will be caused to swing instantly to opposite on and o positions by operation of the lever. If the lever I5 is swung from the full line position represented in Fig. 2, to the left into the position indicated by dotted lines in said figure, rst of all the spring I4 brought within the cavity into the bent position is stretched and then tightened. As soon as the upper end fixed at I6 has advanced far enough to the left, the contact part I operated upon through the lower end I2, which thus far has been at rest, will vbe suddently pulled around (likewise into the position represented by dotted lines), thereby effecting the switching action.

In this switching action, any shock of movement which might otherwise be too great without a cushioning by some well-known arrangementsuch for instance as special rubber-buffers-is prevented merely by theV U-shaped formation of the recessing in the arms I1 of the switching lever, as well as by the springs I4 themselves, effecting the sudden switching action in a self-cushioned and shockless manner. It is easy to round' off the surfaces 20 of the recessing against which the springs lean in vone arrested position or the other,

in such manner that a cushioning of the shock will be eifected over a comparatively long part of the switching or swing movement.

'I'he tumbler switch thus far described is encased by a cap or cover K (see Fig. 4), having a slit S through which the handle-part 24 of the lever fork I protrudes. In the present instance, this handle 24 is hollowed out and the entire lever structure of course consists of a light-coloured and transparent material. A crown or hood strip 25 of transparent material, partly globular or partly cylindrical, is further laid spportively upon the shoulders formed by the fork-arms I'I and fits with a central aperture over the part 24. This shrouds or shades the lamp applied in the socket 'or bushing therebelow. Outwardly said strip bears guidively against ribbed projections 26 formed thereover on the inside of the cap K. When the lamp is lightedl and glows in the respective position of connection (especially nonswitching of the external circuits of a lighting installation), the strip 25 will shine outwardly through the slit S, thus indicating-the location of the switch. For this purpose of course the lamp -in its holding socket makes contact with conductor elements connected with the line attachments of the switch so as to allow sufcient current passage through the lamp when the switch is thrown to off position, or when the switch is .either oif or "on. 'Ihe lower end of the lamp is shown resting on a contact 28 which connects with one terminal post of the switch, and its ferrule bears against another contact 29 (see Fig. 3) connecting with the other post of the switch. These opposite terminal posts are conventionally represented in Fig. 3, but it will be understood that they may be variously provided in know Ways.

The switch of the illustrative embodiment is designed for use both as a circuit-breaker and as a pole-changing switch, this form being selected to exemplify the invention because it is the one in most general use. As a matter of course, the invention is not in any way bound to this one special type of switch only; and for such reason no further description of the internal structure or arrangements of the contact-springs has been made. It is sufiicient to say that the contact piece opens and closes the circuit between the terminal posts with itsl swing to opposite positions. l

Having now particularly described and ascertained the nature of mysaid invention, and in whatv manner the same is to be performed, I declare that what I claimis:

1. An electric switch including a miniature incandescent glow-lamp for indicating in darkness the location of the switch when the same is thrown to off position, comprising in combination, an insulate base, a shell socket xed centrally in the. base and within which the lamp is fitted by screwing, the said shell socket also being an insulate and having its upper part formed into pivot bearings for a swinging contact member, a U-shaped metallic swinging contact-piece having ends engaged in said bearings under spring tension, springs connected on opposite sides to said contact piece, and a forked throw lever to which said springs are also connected, the said lever being pivoted under the spring tension on bearings formed in the base below the pivot axis of said contact-piece and adapted by action of the springs between the two to swing the contact piece with snap action into opposite on and off positions by throw of the lever in alternate directions.

2. An electric switch according to claim 1 wherein the bearings for the ends of the swinging contact-piece comprise inverted cup-shaped cavities `formed in upper-end reinforcing enlargement portions of the shell socket.

3. An electric switch according to claim 1 wherein the forked throw lever has recesses formed in the sides of its fork portions facing the iamp socket therebetween and shaped in such manner that in cooperation with the lsprings connected thereto within said recesses the final movement of the contact piece inv switching will be cushioned.

4. An electric switch according to claim 1 wherein the throw lever is made of transparent material and its fork-like portions serve to support a separate hooding strip of transparent material providing a shield inside the switch for the lamp while allowing the light therefrom to penetrate outwardly'to indicate the position of the switch.

5. An electric switch according to claim 1 wherein the throw lever is made of transparent material and its fork-like portions serve to support a separate hooding strip of transparent material providing a shield inside the'switch for the lamp while allowing the light therefrom to penetrate outwardly to indicate the position of the switch; the said separate strip of transparent material being arcuated and flush with the inner top surface of a cover applied over the entire struc- 70[ ture in unity therewith.

HERMANN NABAKOWSKI. 

